1. Field of the Invention
This invention relates to devices used for the cleaning of animal teeth and gums.
2. Background Information
Cleaning of teeth is very important because unclean teeth are primarily responsible for the most common disease encountered in human and animal medicine--gingivitis and periodontal disease (or periodontitis). Periodontal disease is a term used to describe diseases of the tooth attachment apparatus, the gums, tooth roots, bone surrounding the teeth, and the periodontal ligament tissue joining tooth to bone. Symptoms range from gum inflammation (gingivitis), formation of plaque (food and bacteria), and bad breath (halitosis), to serious accumulation of tartar (mineralized plaque), bleeding, receded or eroded gums, loose or infected teeth, and eventual loss of teeth. Periodontal disease is also the major cause of bad breath in human beings, dogs, and cats. If untreated, periodontal disease often leads to severe damage of major organ systems, and can shorten the life of the afflicted animal. Thus, teeth cleaning is essential to good health.
The permanent dentition of the dog comprises of 42 teeth, compared to 32 teeth in human beings. There are four different types of teeth, the incisors, the canine teeth (fangs), the premolars and the molars. Incisor teeth are predominantly used for grabbing (prehending) food and grooming (nibbling skin). Canine teeth (fangs) are predominantly used for defense and attack, and tearing apart flesh into smaller pieces in order to eat. Premolar teeth are predominantly used for shearing food into smaller chunks. Molar teeth are predominantly used to grind and chew food into smaller pieces that can be swallowed.
When a dog chews food or objects (such as chewing devices), most of this action involves the posterior (caudal) teeth. More specifically the teeth used in this action are the carnassial teeth. The carnassial teeth consist of the upper fourth premolars and the lower first molars.
Due to the shape and arrangement of the posterior (caudal) teeth and due to the openings of the zygomatic and parotid salivary ducts (just above the upper posterior (caudal) teeth), dental plaque and tartar (calculus) accumulate more predominantly on the posterior (caudal) teeth, especially the upper posterior (caudal) teeth. Also, plaque and tartar (calculus) accumulates most commonly on the lateral (buccal) surfaces of the posterior (caudal) teeth. More specifically, tartar (calculus) accumulates most commonly on the lateral (buccal) surfaces of the upper third premolar, the upper fourth premolar, the upper first molar, the lower fourth premolar and the lower first molar. Wild animals keep their teeth relatively clean because they have to work at their food. When they tear a carcass apart to eat, there is considerable abrasion of the teeth by the skin, flesh, tendons, bones and hair of the prey.
Today's pets have the benefit of complete and nutritionally balanced diets, but its presentation in either canned or dried form is not the same as a "natural" diet. Today's canned foods are the main problem. They are sticky and do nothing to clean the teeth. Dry food or biscuits may help slightly in cleaning the teeth, but are still not very effective. Tongue movement, during and after eating and while panting, can help keep the medial (lingual) surfaces clean to a slight extent.
Domestic dogs and cats have a remarkably similar incidence of dental disease to people. Toothbrushing, with a special pet toothbrush and pet toothpaste, is one good way to control or prevent dental disease. Other oral hygiene aids, in conjunction with brushing, may improve the results. However, since toothbrushing of pet's teeth is not usually complied with properly by most people, other oral aids, that the pet can use by itself, become more important. Chew sticks, rubber toys and other so called oral aids, do not help much in cleaning the lateral (buccal) or medial (lingual or palatal) surfaces of the teeth, or under the gumline, where the plaque and tartar (calculus) accumulates most commonly. When an animal chews on such objects, they contact the tips of the teeth, but do not contact the side of the teeth.
Therefore, a need was perceived for an animal dental hygiene device which a pet could use by itself and which would effectively clean animal's teeth and under the gumline.